Economic evaluation study (CHEER-compliant): Cost-effectiveness analysis of RAS screening for treatment of metastatic colorectal cancer based on the CALGB 80405 trial

Abstract

Cetuximab (Cetux)/Bevacizumab (Bev) treatments have shown considerably survival benefits for patients with metastatic colorectal cancer (mCRC) in the last decade. But they are costly. Currently, no data is available on the health economic implications of testing for extended RAS wild-type (wt) prior to Cetux/Bev treatments of patients with mCRC. This paper aimed to evaluate the cost-effectiveness of predictive testing for extended RAS-wt status in mCRC in the context of targeting the use of Cetux/Bev.Markov model 1 was conducted to provide evidence evaluating the cost-effectiveness of predictive testing for KRAS-wt or extended RAS-wt status based on treatments of chemotherapy plus Cetux/Bev. Markov model 2 assessed the cost-effectiveness of FOLFOX plus Cetux/Bev or FOLFIRI plus Cetux/Bev in extended RAS-wt population. Primary base case data were identified from the CALGB 80405 trial and the literatures. Costs were estimated from West China Hospital, Sichuan University, China. Survival benefits were reported in quality-adjusted life-years (QALYs). The incremental cost-effectiveness ratio (ICER) was calculated.In analysis 1, the cost per QALY was $88,394.09 for KRAS-Cetux, $80,797.82 for KRAS-Bev, $82,590.72 for RAS-Cetux, and $75,358.42 for RAS-Bev. The ICER for RAS-Cetux versus RAS-Bev was $420,700.50 per QALY gained. In analysis 2, the cost per QALY was $81,572.61, $80,856.50, $80,592.22, and $66,794.96 for FOLFOX-Cetux, FOLFOX-Bev, FOLFIRI-Cetux, and FOLFIRI-Bev, respectively. The analyses showed that the extended RAS-wt testing was less costly and more effective versus KRAS-wt testing before chemotherapy plus Cetux/Bev. Furthermore, FOLFIRI plus Bev was the most cost-effective strategy compared with others in extended RAS-wt population.It was economically favorable to identify patients with extended RAS-wt status. Furthermore, FOLFIRI plus Bev was the preferred strategy in extended RAS-wt patients.

Figure 1

Overview of the Markov models. Simulation represents the transitions of the hypothetical cohorts through various health states from commencement of Stable Disease to Death. Bev = Bevacizumab, Cetux = Cetuximab, FOLFIRI = irinotecan, leucovorin, fluorouracil, FOLFOX = oxaliplatin, leucovorin, fluorouracil, mCRC = metastatic colorectal cancer.

Figure 2

Cost-effectiveness plane. Bev = Bevacizumab, Cetux = Cetuximab, FOLFIRI = irinotecan, leucovorin, fluorouracil, FOLFOX = oxaliplatin, leucovorin, fluorouracil, QALM = quality-adjusted life-month. dominated, defines a strategy that is either more costly and/or less effective than at least one other strategy.

Figure 3

Tornado diagrams of 1-way sensitivity analyses. Bev = Bevacizumab, Cetux = Cetuximab, FOLFIRI = irinotecan, leucovorin, fluorouracil, FOLFOX = oxaliplatin, leucovorin, fluorouracil, ICER = incremental cost-effectiveness ratio, p = transition probability, PD = progressive disease, SD = stable disease, QALY = quality-adjusted life-years.